Survival improved by stereotactic radiosurgery alone in adults under 50 years with limited brain metastases

Overall survival was improved for adults age 50 years and younger with brain cancer who were treated with stereotactic radiosurgery that was not combined with whole-brain radiotherapy. Also, these patients under age 50 years were at no greater risk for new brain metastases developing, even when whole-brain radiotherapy was omitted. This research was presented at the 55th annual meeting of the American Society for Radiation Oncology in Atlanta, Georgia.

Stereotactic radiosurgery is a highly advanced brain cancer treatment that uses precisely focused radiation beams to treat a tumor with a high dose while minimizing exposure to the surrounding healthy brain tissue. Whole-brain radiotherapy applies radiation therapy to the entire brain, and it is often combined with stereotactic radiosurgery.

This study was a meta-analysis of individual-patient data from three randomized clinical trials. It aimed to evaluate the results of stereotactic radiosurgery alone versus both whole-brain radiotherapy and stereotactic radiosurgery for patients with one to four brain metastases. Patients in this study received one or both types of treatments.

A total of 364 patients from the three RCTs were evaluated. Of those, 51% had been treated with stereotactic radiotherapy alone, and 49% with whole-brain radiotherapy and stereotactic radiotherapy; 19% were 50 years old or younger and 60% had a single brain metastasis. Local brain failure, meaning progression of previously treated brain metastases, occurred in 21% of all patients, and 44% had distant brain failure, which is new brain metastases in areas of the brain outside the primary tumor site(s). A total of 86% of the patients died during follow-up.

The analysis revealed that patients who received only stereotactic radiosurgery had a median of 10 months survival time after treatment, as opposed to 8.2 months survival time for patients who also underwent whole-brain radiotherapy. Overall, local brain failure occurred earlier in patients who received only stereotactic radiotherapy (6.6 months post-treatment), as opposed to patients who also underwent whole-brain radiotherapy (7.4 months post-treatment). Distant brain failure was also earlier overall in patients who received only stereotactic radiosurgery, occurring at 4.5 months post-treatment, compared to 6.5 months post-treatment for patients who also received whole-brain radiotherapy.

“We expected to see a survival advantage favoring combined therapy, given the additional benefits of whole brain radiation, particularly with respect to increasing local control and reducing the risk of new brain metastases,” said lead study author Arjun Sahgal, MD, an associate professor of radiation oncology at the University of Toronto and deputy chief of radiation oncology at Odette Cancer Centre, Sunnybrook Health Sciences Centre in Toronto, Canada. “Our study indicates, however, a survival advantage for stereotactic radiotherapy alone in younger patients who also, interestingly, were observed to have no greater risk of new brain metastases despite the omission of whole brain radiation. Stereotactic radiotherapy alone should be considered as the favored first-line therapeutic option.”